【作者】 李景庆；

【导师】 盛京；

【作者基本信息】 天津大学 ， 材料学， 2007， 博士

【摘要】 聚丙烯（PP）和聚苯乙烯（PS）都是重要的通用热塑性塑料品种,原料来源丰富,合成工艺成熟,且性能互补性强,分子结构中都没有典型的其它元素如N、P、S等,有很好的环保潜质,在汽车、电器、包装及日用品工业等诸多领域应用广泛,若能通过界面增容实现PP、PS优势互补,集中两者优良性能于一体,将在各应用领域相对其它聚合物材料品种具有很强竞争力。本文选用典型路易斯酸无水氯化铝（AlCl₃）作为催化剂,利用烷基化反应机理,对PP/PS合金直接进行原位催化反应增容,以流变学方法（包括静态流变和动态流变学方法）为主,详细探讨无水AlCl₃对PP/PS合金体系中PP和PS两组分的影响,并在此基础上进一步系统研究无水AlCl₃原位催化增容PP/PS合金的相结构演变及增容反应特征,然后对不同原位催化增容条件下获得增容合金材料的流变行为特征作了深入探讨。结果表明,在熔融共混条件下,无水AlCl₃对PP和PS有一定催化降解作用,并可分别在PP和PS中形成C-O-C结构和PS-AlCl₃复合物结构,进而对其流变性能产生复杂影响。无水AlCl₃对PP/PS合金具有原位催化增容作用,产生的PP-g-PS接枝共聚物可在合金相界面处形成具有一定厚度的界面层,且增容作用和PP/AlCl₃和PS/AlCl₃组分的粘度比变化共同影响增容合金相结构的演变,由此产生相界面的大小及同时形成PP碳正离子浓度大小,共同对增容反应产生影响。据线性加和规则,PP/PS合金及增容合金的粘度或模量可分别归结为组分的贡献、几何相结构的贡献及界面粘结作用的贡献,由此可计算原位增容反应引起体系界面粘结作用的大小,所得结果与界面层厚度的演变规律一致。在熔融共混条件下,研究无水AlCl₃对PP/PS/AlCl₃原位催化增容合金中PP、PS组分的影响,进而对增容体系相结构演变、增容反应特征、流变学特征展开研究,有助于深入理解其反应增容机理,阐释增容合金体系的结构与性能特征,进而合理优化PP/PS合金原位催化增容技术,推进相关高性能合金材料的研发。更多还原

【Abstract】 Polypropylene （PP） and polystyrene （PS） are two of the most important thermoplastics because of their abundant resources and convenient industrial production. PP and PS have different merits which are complementary, and in their molecular chains the elements of N, P, and S are all invisible. So PP/PS blends can be widely used in mobiles, electronics, packaging fields, and so on, with precious environmental potentials. And furthermore, if the interfacial adhesion can be improved by compatibilization, the obtained PP/PS alloys would be much more competitive compared with other polymer materials.In this paper, as a typical lewis acid, anhydrous aluminum （AlCl₃） was used as the catalyst to get PP/PS blends compatibilized by in-situ Fridel-Crafts alkylation. The effects on PP and PS components of AlCl₃ were investigated first, mainly by rheology, including steady rheology method and dynamic rheology method. Then the in-situ reactions in PP/PS alloys under different conditions were executed and studied in detail by selective Soxhlet solvent extraction. And at the same time, the evolutions of phase structures of PP/PS and the resulted PP/PS/AlCl₃ alloys were investigated by SEM（Scanning electric morphology） and SALS（Small angle laser scattering）. The steady and dynamic rheological behaviors of in-situ compatibilized PP/PS alloys were obtained systematically.The results showed that, under melt mixing conditions, PP or PS degradation would take place catalyzed by AlCl₃, but not very seriously with lower AlCl₃ content. And at the same time, C-O-C structure and PS-AlCl₃ complex would be formed in PP/AlCl₃ and PS/AlCl₃, respectively, resulted in complex rheological behaviors of systems. In-situ compatibilized reaction of Fridel-Craft alkylation in PP/PS/AlCl₃ alloys catalyzed by AlCl₃ may form PP-g-PS copolymer distributed in interfacial surfaces as interfacial layer with a certain depth. The effects of compatibilization and the ratio of viscosities of PP/AlCl₃ and PS/AlCl₃ determined the evolution of phase structures of PP/PS/AlCl₃, together. And the compatibilization reaction was influenced by the area of interfacial surfaces and the concentration of PP+ ion in the reactive system. According to log-linearly additivity method, storage modulus, loss modulus, complex modulus and complex viscosity of PP/PS alloys or compatibilized PP/PS/AlCl₃ alloys could be divided into three parts, including contribution of components, contribution of geometrical phase structure, and contribution of the interfacial adhesion of phases. Thus the contribution of PP or PS component and contribution of geometrical phase structure could be separated away and contribution of interfacial adhesion of in-situ compatibilization could be calculated out. The dependence of interfacial adhesion on compositions calculated from static rheology and dynamic rheology, especially, was the same to the dependence of PP-g-PS yield determined by soxhlet extracted method, and also was the same to the dependence of interfacial layer thickness d obtained by SALS.Investigations on the influences of AlCl3 on PP and PS under melt mixing conditions and on the resulted phase structure evolutions, reactive characteristics, and rheological properties of PP/PS/AlCl3 alloys were helpful to understand the reactive mechanism, to explain the characteristic structure and property changes of alloys, and to prepare better PP/PS alloys with competitive potentials.更多还原